This invention relates generally to improvements in medical test devices and kits used for collecting and analyzing biological specimens. More particularly, this invention relates to an improved reagent dispenser and related test kit of the general type described in U.S. Pat. No. 5,266,266, with means for mixing and delivering multiple reagents for contact with a biological specimen in the course of performing a medical analysis or the like.
Medical swabs are generally known in the art for use in collecting biological specimens from a patient for further analysis. Such medical swabs commonly comprise a fibrous swab tip at one end of an elongated stick or shaft which is manually handled to contact the swab tip with selected tissue cells or other biological specimen obtained, for example, within the ear, nose or throat of a patient. As a result, some of the targeted biological specimen adheres to the swab tip which then can be contacted with one or more chemical reagents to indicate the presence of infection or other information regarding patient condition. Tests commonly performed with such patient specimens include, by way of example, fluorescent tests, enzymatic tests, monoclonal based tests, agglutination tests, and others.
In accordance with standard specimen collection and test preparation techniques, the biological specimen is normally transferred from the swab tip to a slide or other laboratory apparatus such as a test tube or the like for contact with the selected reagent and further analysis. However, it is frequently difficult to ensure transfer of a sufficient specimen quantity from the swab tip to the laboratory slide or test tube to ensure accurate test results. Moreover, in many instances, the collected specimen must be transported to an off-site medical laboratory for performance of selected assays, but delays between the time of specimen collection and actual test performance can result in partial or complete drying of the specimen, with a corresponding decrease in test reliability.
Various swab-type collection and test devices have been proposed in efforts to provide enhanced contact between a specimen and reagent, or, in the alternative, to sustain the specimen for post-collection transport to a medical laboratory. Such swab collection devices have been provided in the form of a compact kit including a fibrous-tipped swab together with one or more reagents for contacting a specimen collected on the swab tip. In some designs, the reagent is sealed within a frangible glass ampoule which is broken at the appropriate time to release the reagent for contacting the specimen on the swab tip. See, for example, U.S. Pat. Nos. 4,792,699; 4,978,504; 5,078,968; and 5,238,649. The glass ampoule, however, comprises an additional and relatively costly component to the collection device or kit. Moreover, the glass ampoule produces sharp fragments or shards when broken, wherein the collection device must be designed to prevent the glass fragments from contacting the collected specimen or medical personnel.
Alternative swab-type collection devices have envisioned reagent placement within a rupturable cell or compartment formed within a plastic swab housing. See, for example, U.S. Pat. No. 4,707,450. In these designs, the reagent cell or compartment is opened at the appropriate time to permit reagent release for flow into contact with a collected specimen on the swab tip. While this approach avoids the disadvantages associated with glass ampoules, the manufacture of plastic housings with liquid-filled compartments adapted for controlled rupture has been relatively difficult and generally unreliable.
U.S. Pat. No. 5,266,266 discloses a further improved swab-type specimen test device, wherein a reagent is contained within a sealed compartment which is opened at the appropriate time by manipulating a break-off nib. This device beneficially avoids the use of glass ampoules and further provides for reliable and controlled reagent release in a cost-efficient design.
For some specimen analyses, it is necessary or desirable to mix multiple reagents together prior to contacting the specimen, wherein the mixed reagents are sufficiently unstable to require that they be maintained in separate sealed chambers until the test is to be performed. Prior swab-type specimen test devices have not satisfactorily addressed such applications.
The present invention is directed to an improved reagent dispenser device, particularly of the type having a break-off nib, for maintaining multiple reagents in separate chambers for convenient mixing and delivery at the appropriate time to contact a collected specimen.